In recent years, the development of the liquid crystal display has presented a development trend of high integration and low cost. One of the very important technologies is the realization of mass production of the gate driver on array (GOA) technology. The GOA technology is a technology that forms the gate drive circuit on an array substrate directly to replace the driver wafer fabricated by an external wafer. The application of the GOA technology can simplify the fabricating process, reduce the product cost, improve the integration of the display panel, and enable the panel to be thinner. Such a circuit integrated on the array substrate using the GOA technology is also called a GOA circuit.
The shift register circuit (i.e., the gate drive circuit) generally includes several shift register unit circuits (i.e., gate drive unit circuits). As shown in FIG. 1, in the shift register unit circuit of the prior art, the pull-up node PU and the pull-down node PD are generally designed to be inverters for each other; hence, when the pull-up node PU is charged, a direct current generally passes through the pull-down node PD, thereby resulting in loss of the direct current. In addition, the shift register unit circuit has a relatively poor stability. If the variation of the characteristics, particularly the threshold voltage of the thin film transistors (TFT) that form the circuit reaches a certain degree, the shift register unit circuit will not work normally. For example, as shown in FIG. 1, if the threshold voltage of the TFT M10 drifts in a negative direction, the electric leakage of the pull-up node PU through the TFT M10 will increase; hence, the problem that the pull-up node PU cannot be charged normally will occur. Thus, the potential of the pull-down node PD cannot be pulled down by the pull-up node PU either, thereby resulting in failure of normal output.